Field
The present disclosure relates generally to vertical LEDs and, more particularly, to vertical LEDs having light output that is similar to the light output by lateral LEDs.
Background
Solid state light emitting devices, such as light emitting dies (LEDs), are attractive candidates for replacing conventional light sources such as incandescent, halogen, and fluorescent lamps. LEDs have substantially longer lifetimes than all three of these types of conventional light sources. In addition, some types of LEDs now have higher conversion efficiencies than fluorescent light sources and still higher conversion efficiencies have been demonstrated in laboratories. Finally, LEDs contain no mercury or other potentially dangerous materials, therefore, providing various safety and environmental benefits.
Several different LED designs exist today, including vertical LEDs and lateral LEDs. Vertical LEDs have been considered as a replacement for lateral LEDs in array packages because vertical LEDs perform better than conventional lateral LEDs. However, simply using a vertical LED as a “drop-in” replacement for a lateral LED produces a 20% lumen drop in most LED chip-on-board configurations due to the occurrence of light absorbing effects between LEDs. Therefore, it is difficult to use vertical LEDs as a replacement for lateral LEDs without additional optimization to account for the lumen drop.